This invention relates to aqueous halogenated amide antimicrobial compositions having improved stability and to processes for their preparation.
Halogenated amides such as 2,2-dibromonitrilopropionamide are useful as antimicrobials in various applicaions. See, for example, Nolan et al., U.S. Pat. No. 2,419,888; Schmidt et al., U.S. Pat. No. 3,493,658; and CIBA S.A. Belgian Pat. No. 668,336. Certain halogenated amides are useful in the finishing of textiles, as taught by Chance et al., U.S. Pat. Nos. 3,350,164 and 3,403,174. Others are useful as slimicides in aqueous systems such as paper pulp and cooling towers and as sterilizing agents for dry cleaning fluids. See, for example, Wolf, U.S. Pat. No. 3,647,610; Wolf, U.S. Pat. 3,649,166; Wolf et al., "2,2-Dibromo-3-Nitrilopropionamide, A Compound with Slimicidal Activity", Applied Microbiology, Vol. 24, No. 4, pp. 581-584 (1972); and Moyle et al., U.S. Pat. No. 3,928,575.
In the storage, shipment and use of the aforementioned halogenated amide antimicrobial agents, it has heretofore been suggested to employ such antimicrobial agent in the form of a liquid concentrate composition wherein the halogenated amide is dissolved either in a straight chain polyalkylene glycol or in a mixture of such glycol with up to about 20 weight percent water on a total weight basis. Unfortunately, however, the presence of water in such compositions has been found to accelerate the decomposition of the halogenated amide therein and, indeed, at water contents above 20 weight percent the stability of the halogenated amide in the resulting aqueous compositions has been reported to be entirely unsatisfactory. See U.S. Pat. No. 3,689,660 and "Rates and Products of Decomposition of 2,2-Dibromo-3-Nitrilopropionamide," Exner et al., J. Arg. Food Chem., Vol. 21, No. 5, pp. 838-842 (1973). Thus, in order to obtain adequate stability for most purposes, it has heretofore been generally necessary to either resort to essentially anhydrous liquid concentrate compositions or to at least limit the water content of such compositions to less than about 20 weight percent on a total weight basis. Similarly, it has also heretofore generally been necessary either to essentially exclude water from the ingredients used in the preparation of such compositions or at least to substantially limit the water content of such ingredients.
In view of the foregoing, it is highly desirable to provide a means of reducing the adverse impact of water upon the aforementioned liquid compositions and to thereby provide (a) aqueous halogenated amide antimicrobial compositions having improved stability and (b) an economical process for the preparation of suitably stable aqueous halogenated amide antimicrobial compositions. Moreover, it is especially desirable to provide such aqueous halogenated amide antimicrobial compositions (and preparation processes therefor) which have acceptable stability of the halogenated amide antimicrobial therein even at water contents in excess of 20 weight percent based on the total weight of such aqueous antimicrobial composition.